Flat wire conveyor belts have been in the market for many years. Flat wire conveyor belts are generally low maintenance and when positively driven with sprockets have little to no lateral shifting.
A known flat wire conveyor belt is shown in U.S. Pat. No. 7,975,840, assigned to Cambridge International, Inc., the entire contents of which are hereby incorporated by reference. The conveyor belt therein includes a plurality of spaced tractive rods disposed in succession and transversely with respect to a direction of travel and a plurality of rows of pickets transversely disposed with respect to the direction of travel, and interconnecting the succession of rods. Each row of pickets is comprised of a plurality of links, each link connecting a rod with a following rod in the succession.
The pickets comprise a plurality of links; however, not all the links within a single picket are identical. More particularly, in order to strengthen the outer edges of the conveyor belt, the edges of the picket are provided with links having a first spacing or mesh size and the middle portion of the belt therebetween is provided with links having a second spacing or mesh size. Hence, the pattern of openings in belt provides both narrow openings for sprocket engagement and wider openings for product support that results in reduced material usage and belt weight, yet still provides sufficient strength for product support.
When such a flat-wire conveyor belt is subjected to large temperature changes, however, expansion/contraction of the overall belt width relative to that of the sprockets and shaft may result in potential binding and belt/sprocket disengagement due to the differential expansion/contraction between the belt and the sprockets and shaft.
Accordingly, there exists a need in the marketplace for a flat wire conveyor belt having a lighter weight and reduced quantity of required material, while still retaining its strength, and which provides for fixed sprocket placement on the conveyor shaft when the belt is subjected to large temperature changes.